Control of micromirrors with intermediate states

ABSTRACT

A micromirror device with at least one intermediate state is disclosed in this invention with the reflecting mirror placed at an angular position between a fully on angle and fully off angle. The micromirror device includes a reflecting element supported on a hinge for oscillating and positioning at least three angular positions. The micromirror device further has a control circuit for receiving a series of control words of different number of bits as a time modulation signal to control the reflecting element for controlling a gray scale of display wherein the control circuit further receiving an oscillation signal for superimposing on the time modulation signal for oscillating the reflecting element for further controlling the gray scale of display. The series of control words further includes a sequence of control words of a least number of bits to a maximum number of bits of a least number of bits to a maximum number of bits with a time gap between each of the control words. The oscillating signal may be inserted optionally into a gap between the control words, into every control word, into a control word of the MSB, or into a control word of the LSB, In a preferred embodiment, the oscillating signal is applied to dispose the reflecting element at an intermediate state with a zero degree relative to an incident light.

This application is a Continuation in Part (CIP) Application of pendingU.S. patent application Ser. No. 10/698,620 filed on Nov. 1, 2003, Ser.No. 10/699,140 filed on Nov. 1, 2003, now U.S. Pat. No. 6,862,127 andSer. No. 10/699,143 filed on Nov. 1, 2003 now U.S. Pat. No. 6,903,860 bythe Applicant of this Patent Applications. The disclosures made in thesePatent Applications are hereby incorporated by reference in this PatentApplication.

TECHNICAL FIELD

This invention relates to micromirror arrays and control circuits tocontrol the micromirrors. More particularly, this invention relates tocontrol circuits for controlling the micromirrors to oscillate throughmultiple angular positions for providing intermediate states toimplement the micromirror array as spatial light modulators (SLMs) thusenabling more accurately controllable gray scales.

BACKGROUND ART

Even though there are significant advances made in recent years on thetechnologies of implementing electromechanical micromirror devices asspatial light modulator, there are still limitations and difficultieswhen employed to provide high quality images display. Specifically, whenthe display images are digitally controlled, the image qualities areadversely affected due to the fact that the image is not displayed withsufficient number of gray scales.

Electromechanical micromirror devices have drawn considerable interestbecause of their application as spatial light modulators (SLMs). Aspatial light modulator requires an array of a relatively large numberof micromirror devices. In general, the number of devices requiredranges from 60,000 to several million for each SLM. Referring to FIG. 1Afor a digital video system 1 disclosed in a relevant U.S. Pat. No.5,214,420 that includes a display screen 2. A light source 10 is used togenerate light energy for ultimate illumination of display screen 2.Light 9 generated is further concentrated and directed toward lens 12 bymirror 11. Lens 12, 13 and 14 form a beam columnator to operative tocolumnate light 9 into a column of light 8. A spatial light modulator 15is controlled by a computer through data transmitted over data cable 18to selectively redirect a portion of the light from path 7 toward lens 5to display on screen 2. The SLM 15 has a surface 16 that includes anarray of switchable reflective elements, e.g., micromirror devices 32,such as elements 17, 27, 37, and 47 as reflective elements attached to ahinge 30 that shown in FIG. 1B. When element 17 is in one position, aportion of the light from path 7 is redirected along path 6 to lens 5where it is enlarged or spread along path 4 to impinge the displayscreen 2 so as to form an illuminated pixel 3. When element 17 is inanother position, light is not redirected toward display screen 2 andhence pixel 3 would be dark.

The on-and-off states of micromirror control scheme as that implementedin the U.S. Pat. No. 5,214,420 and by most of the conventional displaysystem imposes a limitation on the quality of the display. Specifically,when applying conventional configuration of control circuit has alimitation that the gray scale of conventional system (PWM between ONand OFF states) is limited by the LSB (least significant bit, or theleast pulse width). Due to the On-Off states implemented in theconventional systems, there is no way to provide shorter pulse widththan LSB. The least brightness, which determines gray scale, is thelight reflected during the least pulse width. The limited gray scaleslead to degradations of image display.

Specifically, in FIG. 1C an exemplary circuit diagram of a prior artcontrol circuit for a micromirror according to U.S. Pat. No. 5,285,407.The control circuit includes memory cell 32. Various transistors arereferred to as “M*” where * designates a transistor number and eachtransistor is an insulated gate field effect transistor. Transistors M5,and M7 are p-channel transistors; transistors, M6, M8, and M9 aren-channel transistors. The capacitances, C1 and C2, represent thecapacitive loads presented to memory cell 32. Memory cell 32 includes anaccess switch transistor M9 and a latch 32 a, which is the basis of thestatic random access switch memory (SRAM) design. All access transistorsM9 in a row receive a DATA signal from a different bit-line 31 a. Theparticular memory cell 32 to be written is accessed by turning on theappropriate row select transistor M9, using the ROW signal functioningas a wordline. Latch 32 a is formed from two cross-coupled inverters,M5/M6 and M7/M8, which permit two stable states. State 1 is Node A highand Node B low and state 2 is Node A low and Node B high.

The dual states switching as illustrated by the control circuit controlsthe micromirrors to position either at an ON of an OFF angularorientation as that shown in FIG. 1A. The brightness, i.e., the grayscales of display for a digitally control image system is determined bythe length of time the micromirror stays at an ON position. The lengthof time a micromirror is controlled at an ON position is in turnedcontrolled by a multiple bit word. For simplicity of illustration, FIG.1D shows the “binary time intervals” when control by a four-bit word. Asthat shown in FIG. 1D, the time durations have relative values of 1, 2,4, 8 that in turn define the relative brightness for each of the fourbits where 1 is for the least significant bit and 8 is for the mostsignificant bit. According to the control mechanism as shown, theminimum controllable differences between gray scales for showingdifferent brightness is a brightness represented by a “least significantbit” that maintaining the micromirror at an ON position. For practicalimplementation, the control signals with different binary bits areinputted to the control circuits as shown in FIG. 1E. There is generallya small time gap between control words of different bit lengths asshown.

When adjacent image pixels are shown with great degree of different grayscales due to a very coarse scale of controllable gray scale, artifactsare shown between these adjacent image pixels. That leads to imagedegradations. The image degradations are specially pronounced in brightareas of display when there are “bigger gaps” of gray scales betweenadjacent image pixels. It was observed in an image of a female modelthat there were artifacts shown on the forehead, the sides of the noseand the upper arm. The artifacts are generated due to a technicallimitation that the digital controlled display does not providesufficient gray scales. At the bright spots of display, e.g., theforehead, the sides of the nose and the upper arm, the adjacent pixelsare displayed with visible gaps of light intensities.

As the micromirrors are controlled to have a fully on and fully offposition, the light intensity is determined by the length of time themicromirror is at the fully on position. In order to increase the numberof gray scales of display, the speed of the micromirror must beincreased such that the digital control signals can be increased to ahigher number of bits. However, when the speed of the micromirrors isincreased, a strong hinge is necessary for the micromirror to sustain arequired number of operational cycles for a designated lifetime ofoperation, In order to drive the micromirrors supported on a furtherstrengthened hinge, a higher voltage is required. The higher voltage mayexceed twenty volts and may even be as high as thirty volts. Themicromirrors manufacture by applying the CMOS technologies probablywould not be suitable for operation at such higher range of voltages andtherefore the DMOS micromirror devices may be required. In order toachieve higher degree of gray scale control, a more complicatemanufacturing process and larger device areas are necessary when DMOSmicromirror is implemented. Conventional modes of micromirror controlare therefore facing a technical challenge that the gray scale accuracyhas to be sacrificed for the benefits of smaller and more cost effectivemicromirror display due to the operational voltage limitations.

There are many patents related to spatial light modulation that includesU.S. Pat. Nos. 2,025,143, 2,682,010, 2,681,423, 4,087,810, 4,292,732,4,405,209, 4,454,541,4,592,628, 4,767,192, 4,842,396, 4,907,862,5,214,420, 5,287,096, 5,506,597, and 5,489,952. However, theseinventions have not addressed and provided direct resolutions for aperson of ordinary skill in the art to overcome the above-discussedlimitations and difficulties.

Therefore, a need still exists in the art of image display systemsapplying digital control of a micromirror array as a spatial lightmodulator to provide new and improved systems such that the abovediscussed difficulties can be resolved.

SUMMARY OF THE INVENTION

The present invention relates to control circuits for micromirrordevices and arrays of micromirror devices. The purpose of controllingthe arrays is to apply such array as spatial light modulators (SLMs). Inone aspect, the present invention provides a micromirror device in whichthe reflecting element is controlled to reflect light for image displayat multiple intermediate positions for providing more flexiblycontrollable gray scales of display without requiring a higher speed ofmicromirror oscillation thus maintaining a low operational voltage.

In another aspect, the present invention provides a micromirror deviceoperated with an ON state, an OFF state and an intermediate Oscillatingstate.

In yet another aspect, the present invention provides a micromirrordevice comprising an array of micromirrors that are controlled tooperate with intermediate oscillating states to provide a leastbrightness that is a fraction, e.g., approximately 37%, of the fully ONstate. The gray scale for display is now controllable to project finerscale of brightness differences between adjacent pixels with anadditional controllable state to provide a fraction of brightness of thefully-on state for display. The annoying artifacts shown on a displaycaused by adjacent pixels having huge gray scale gaps can besignificantly reduced.

In yet another aspect, the present invention provides a method ofcontrol the oscillation an array of micromirror devices wherein themicromirrors are enabled to oscillate in a reverse direction or stopbefore the micromirror completes a full oscillation cycle. Aided by suchcontrol flexibility and the fractional brightness for image displayduring an intermediate oscillation state, additional flexibilities arenow provided to fine tune the gray scale for each image pixel especiallyfor the high brightness display area where a gray scale difference areproportionally amplified due to the high intensity of light projections.

These and other objects and advantages of the present invention will nodoubt become obvious to those of ordinary skill in the art after havingread the following detailed description of the preferred embodiment,which is illustrated in the various drawing figures.

BRIEF DESCRIPTION OF FIGURES

The present invention is described in detail below with reference to thefollowing Figures.

FIGS. 1A and 1B are functional block diagram and a top view of a portionof a micromirror array implemented as a spatial light modulator for adigital video display system of a conventional display system disclosedin a prior art patent.

FIG. 1C is a circuit diagram for showing a prior art circuit forcontrolling a micromirror to position at an ON and OFF states of aspatial light modulator.

FIG. 1D is diagram for showing the binary time intervals for a four bitgray.

FIG. 1E is a timing diagram for illustrating practical implementation ofthe eight bits control word ranging from the least significant bit (LSB)to the most significant bit (MSB).

FIG. 2 is a side cross sectional diagram of a micromirror device of thisinvention wherein the micromirror is oscillating between an ON-OFFposition for providing at least an intermediate state.

FIG. 3 is a diagram for showing the micromirror angle versus time forcomputing an illumination to display an image with different lightintensities wherein one-oscillating cycle provides approximately 37%light intensity of the fully-on state.

FIG. 4 is a circuit diagram for controlling a micromirror of thisinvention.

FIG. 5A is a diagram for showing the change of micromirror states overtime wherein the micromirror may be controlled to position at threedifferent states.

FIG. 5B is a diagram for showing the micromirror oscillation from oneposition to a different positions according to the different statesshown in FIG. 5A.

FIG. 5C is a diagram for showing the brightness as the micromirroroscillating between different states according to that shown in FIGS. 5Aand 5B.

FIG. 6A to 6D are timing diagrams for showing the different time slots amirror oscillation signal may be inserted to adjust the angularpositions of the micromirrors.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIG. 2 for a side cross sectional view for illustrating theoscillating motions of a micromirrors according to the control circuitof the present invention. A micromirror 100 supported on a hinge 110formed on a substrate (not shown), is electrically controlled by twoelectrodes 120-1 and 120-2 to move to different positions, e.g., from+12 degrees to −12 degrees as shown. The incident light is projectedalong an optical path 130 and the light reflected from the micromirror100 is projected to a projection lens 125 for further projecting to adisplay surface (not shown). The mirror surface is multi-layer toachieve higher reflection. An Aluminum surface can provide 90-92%reflectance but multi-layer can provide a higher reflection up to 98%.The micromirror is controlled to move to a full-on state when themicromirror is positioned at the +12 degrees with the reflected lightprojected fully onto the projection lens along a 140 directionperpendicular to the projection lens 125. The micromirror 100 iscontrolled to move to a full-off state when the micromirror 100 ispositioned at a −12 degrees with the reflected light 150 totally missesthe projection lens 125. In a preferred embodiment, the micromirror 100is controlled to move to an intermediate state when the micromirror iscontrolled to move to a zero degree position when the reflected light isprojected along a third state direction 160. In different preferredembodiments, the micromirrors can be oscillating between a positive andnegative angle relative to a perpendicular axis to the surface of themicromirror. The fully on and fully off positions as defined by thesepositive and negative angles can be flexibly designed depending on thesystem specifications for each specific application.

Referring to FIG. 3 for a waveform diagram showing the mirror angularposition changes with time as the micromirror oscillates from the onstate to an off state. A computation is performed to compute the lightprojection through the projection lens 125 for image display. During anoscillating condition, there is 37% of the light of the fully on state.For example, if 20 microseconds of an ON time provide a light output ofone lumen, then the one oscillating cycle provides 0.37 lumen output oflight. For the purpose of minimize oscillation decay of the micromirrors100, the micromirror array is contained and operated in a vacuum-sealedenvironment. With a partial light projection of light to contribute tothe image light intensity, a higher number of gray scales are achievablewithout requiring a high speed of mirror oscillation. The micromirrordevices can be controlled at a voltage substantially lower than twentyvolts, e.g., around five volts, such that the spatial light modulator(SLM) can be implemented with CMOS technologies. Optionally, the SLM canalso be implemented with DMOS, PMOS and NMOS technologies.

Referring to FIG. 4 for a preferred embodiment showing a control circuitto control the oscillation of the micromirror 100 to position at an ONstate, an OFF state and an intermediate state based on the ON-OFF statesof the electrodes 120-1 and 120-2. The control circuit includes awordline 160 and two bit-lines 170-1 and 170-2 to alternate turn on twotransistors 180-1 and 180-2, e.g., FET-1 and FET-2 respectively. Each ofthese transistors 180-1 and 180-2 is connected to a capacitor 185-1 and185-2, e.g., Cap-1 and Cap-2 respectively. Each micromirror for displayof one pixel is therefore control to have multiple states depending onthe input to the bit-lines 170-1 and 170-2. Specifically, the controltable can be represented as the followings:

TABLE 1 Bit #1 Bit #2 State 1 0 ON 0 1 OFF 0 0 Intermediate 1 1Undefined

Referring to FIG. 5 for an exemplary timing diagram for illustrating thechanges of control states between a first state, an intermediate stateand a second state. The first state is a fully ON state to provide ahighest brightness. The second state is an OFF state to provide a lowestbrightness. Additionally, there is an intermediate state as a thirdstate for providing flexibility to adjust brightness thus controls thegray scale of each image pixel.

As shown in the timing diagram of FIG. 5A and FIG. 5B, the oscillatingmicromirror is provided with flexibility to oscillate between the first,second and third states. The micromirror is oriented at +12 degrees at afist state. The micromirror is oriented at a −12 degrees at a secondstate and oriented at zero degree at an intermediate state. either atthe end of the oscillating cycles or in an intermediate points that maybe a fraction of an oscillating cycle.

As shown in the timing diagram of FIG. 5C, the brightness of an imagepixel as projected from a micromirror is a function of the length of thetime the micromirror stays at a certain states and also is a function ofthe fraction of light when the mirror oscillates and stays at anintermediate state. FIG. 5C clearly shows that the gray scale can beflexibly controlled with much greater degree of accuracy since the grayscale is no longer limited by the least significant bit of the controlword.

Therefore, in this invention, the gray scales can be controlled bycontrolling the durations of the micromirror positioned at threedifferent states. Furthermore, oscillation of the micromirrors iscontrollable to swing from one state to another state at a mid-point ofan oscillation cycle. The gray scale GS is therefore functional dependson Ts1, Ts2, and Ts3 that represent lengths of time the micromirror ispositioned at different three states, and also depends on the lengths oftime for the micromirror to change from one state to another since therewill be partial projection of the light to the image pixel from as themicromirror swing through at least one intermediate state.

Referring to FIGS. 6A to 6D for a time diagram for showing differentmethods for inserting the oscillation control signals for initiating amicromirror oscillations. In FIG. 6A, the oscillation control signal areinputted to the control circuit at the end of each control word while inFIG. 6A, the oscillation control signal is inputted to the controlcircuit right after the time cycle of each control word of different bitlengths. In FIG. 6C, the oscillation control signal is inputted to thecontrol signal after the entire eight-bit control words are completelyprocessed. In FIG. 6D, the control signal is inserted into a time slotin the time period represented by the timing control word that has themost significant bit (MSB).

In a preferred embodiment, this invention further discloses a method forcontrolling a micromirror that includes a step of controlling areflecting element supported on a hinge to oscillate between two statesand enabling said reflecting elements to project a partial light forcontributing to a display light intensity during oscillating betweeneither of said two states.

Although the present invention has been described in terms of thepresently preferred embodiment, it is to be understood that suchdisclosure is not to be interpreted as limiting. Various alternationsand modifications will no doubt become apparent to those skilled in theart after reading the above disclosure. Accordingly, it is intended thatthe appended claims be interpreted as covering all alternations andmodifications as fall within the true spirit and scope of the invention.

1. A micromirror device comprising: a reflecting element supported on ahinge for oscillating and positioning at least three angular positions;and a control circuit for receiving a series of control words ofdifferent number of bits as a time modulation signal to control saidreflecting element for controlling a gray scale of display wherein saidcontrol circuit further receiving an oscillation signal forsuperimposing on said time modulation signal for oscillating saidreflecting element for further controlling said gray scale of display;and said oscillating signal is provided for controlling said reflectingelement to oscillated to a fully on, a fully off and an partially ONangular positions wherein said reflecting element is further controlledby said oscillating signal to change an oscillation direction in anintermediate angular position between said fully on and fully offangular positions.
 2. The device of claim 1, wherein: said series ofcontrol words further includes a sequence of control words of a leastnumber of bits to a maximum number of bits.
 3. The device of claim 1,wherein: said series of control words further includes a sequence ofcontrol words of a least number of bits to a maximum number of bits witha time gap between each of said control words.
 4. The device of claim 3,wherein: said oscillating signal is received as a two bit signal.
 5. Thedevice of claim 3, wherein: said oscillating signal is inserted intoeveryone of said series of control words.
 6. The device of claim 3,wherein: said oscillating signal is inserted into a gap between saidcontrol words.
 7. The device of claim 3, wherein: said oscillatingsignal is inserted into a control word of said least number of bits. 8.The device of claim 3, wherein: said oscillating signal is inserted intoa control word of said maximum number of bits.
 9. The device of claim 3,wherein: said oscillating signal is inserted into a gap between everytwo of said control words.
 10. The device of claim 3, wherein: saidoscillating signal is applied to dispose said reflecting element at anintermediate state with a zero degree relative to an incident light. 11.The device of claim 1, wherein: said reflecting element is furtherprovided for oscillating to said fully on, a fully off and an partiallyON angular positions in responding to said series of control words andsaid oscillating signal inputted as digital control signals.
 12. Thedevice of claim 1, wherein: said reflecting element is furthercontrolled by said oscillating signal inputted as a two-bit digitalcontrol signal.
 13. The device of claim 1, further comprising: twoelectrodes for inputting said oscillating signal for oscillating saidreflecting element to different positions.
 14. The device of claim 1,further comprising: two electrodes for inputting said oscillating signalrepresenting by two digital bits with one bit applied to each of saidtwo electrodes for changing a voltage applied thereon for oscillatingsaid reflecting element to different positions.
 15. The device of claim1, further comprising: a lens for receiving an incident light projectionfrom said reflecting element for projecting an image display lightwherein said lens is further disposed for projecting a portion of saidimage display light as said reflecting element oscillating between afully on and fully off angular positions.
 16. The micromirror device ofclaim 1 further comprising: a vacuum seal package for enclosing saidreflecting element and said hinge in a sealed vacuum space.
 17. Thedevice of claim 1, further comprising: two separate independentlycontrollable electrodes for inputting said oscillating signal forcontrolling said reflecting element to oscillate to different positions.18. The device of claim 1, further comprising: two separateindependently controllable electrodes for inputting said oscillatingsignal wherein said two separate independently controllable electrodesdisposed on two opposite sides of said hinge and each of said electrodesis connected to a control circuit for independently applying a controlvoltage thereon to control said reflecting element to oscillate todifferent positions.
 19. The device of claim 18, wherein: each of saidelectrodes is connected to a transistor having a gate connected to acommon wordline and each transistor having a source connected to anindependently controllable bitline for independently controlling saidreflecting element to oscillate to different positions.
 20. The deviceof claim 19, wherein: each bitline connected to said source of saidtransistor is provided for receiving a binary bit represented by zeroand one for applying a voltage to said electrodes for independentlycontrolling said reflecting element to oscillate to different positions.21. The device of claim 19, wherein: each bitline connected to saidsource of said transistor is provided for receiving a binary bitrepresented by zero and one for applying a voltage to said electrodesfor applying one of three digital signals represented by (1,0), (0,1)and (0,0) for controlling said reflecting element to oscillate to threedifferent positions.
 22. The device of claim 19, wherein: each bitlineconnected to said source of said transistor is provided for receiving abinary bit represented by zero and one for applying a voltage to saidelectrodes for applying one of three digital signals represented by(1,0), (0,1) and (0,0) for controlling said reflecting element tooscillate to angular positions oriented substantially at a positiveangle, a negative angle and 0° relative to a perpendicular axis to saidreflecting element.
 23. A micromirror device comprising: a reflectingelement supported on a hinge for oscillating between two states whereinsaid reflecting elements is projecting a partial light for contributingto a display light intensity during oscillating between either of saidtwo states; a control circuit for receiving a series of control words ofdifferent number of bits as a time modulation signal to control saidreflecting element for controlling a gray scale of display wherein saidcontrol circuit further receiving an oscillation signal forsuperimposing on said time modulation signal for oscillating saidreflecting element for further controlling said gray scale of display;and said oscillating signal is provided for controlling said reflectingelement to oscillated to a fully on, a fully off and an partially ONangular positions wherein said reflecting element is further controlledby said oscillating signal to change an oscillation direction in anintermediate angular position between said fully on and fully offangular positions.
 24. The device of claim 23, wherein: said series ofcontrol words further includes a sequence of control words of a leastnumber of bits to a maximum number of bits.
 25. The device of claim 23,wherein: said series of control words further includes a sequence ofcontrol words of a least number of bits to a maximum number of bits witha time gap between each of said control words.
 26. The device of claim23, wherein: said oscillating signal is received as a two bit signal.27. The device of claim 25, wherein: said oscillating signal is insertedinto everyone of said series of control words.
 28. The device of claim25, wherein: said oscillating signal is inserted into a gap between saidcontrol words.
 29. The device of claim 25, wherein: said oscillatingsignal is inserted into a control word of said least number of bits. 30.The device of claim 25, wherein: said oscillating signal is insertedinto a control word of said maximum number of bits.
 31. The device ofclaim 25, wherein: said oscillating signal is inserted into a gapbetween every two of said control words.
 32. The device of claim 25,wherein: said oscillating signal is applied to dispose said reflectingelement at an intermediate state with a zero degree relative to anincident light.
 33. The device of claim 23, wherein: said partial lightfor contributing to a display light intensity is further applied byusing said oscillation signal for controlling a gray scale of an imagedisplay using a light projected from said reflecting element.
 34. Thedevice of claim 23, wherein: said reflecting element is further providedfor oscillating to a fully on, a fully off and an partially ON angularpositions in responding to said series of control words and saidoscillating signal inputted as digital control signals.
 35. The deviceof claim 23, wherein: said reflecting element is further controlled bysaid oscillating signal inputted as a two-bit digital control signal.36. The device of claim 23, further comprising: two electrodes forinputting said oscillating signal for oscillating said reflectingelement to different positions.
 37. The device of claim 23, furthercomprising: two electrodes for inputting said oscillating signalrepresenting by two digital bits with one bit applied to each of saidtwo electrodes for changing a voltage applied thereon for oscillatingsaid reflecting element to different positions.
 38. The device of claim23, further comprising: a lens for receiving an incident lightprojection from said reflecting element for projecting an image displaylight wherein said lens is further disposed for projecting a portion ofsaid image display light as said reflecting element oscillating betweena fully on and fully off angular positions.
 39. The micromirror deviceof claim 23 further comprising: a vacuum seal package for enclosing saidreflecting element and said hinge in a sealed vacuum space.
 40. Themicromirror device of claim 23, further comprising: two separateindependently controllable electrodes for inputting said oscillatingsignal for controlling said reflecting element to oscillate to differentpositions.
 41. The micromirror device of claim 23, further comprising:two separate independently controllable electrodes for inputting saidoscillating signal wherein said two separate independently controllableelectrodes disposed on two opposite sides of said hinge and each of saidelectrodes is connected to a control circuit for independently applyinga control voltage thereon to control said reflecting element tooscillate to different positions.
 42. The micromirror device of claim41, wherein: each of said electrodes is connected to a transistor havinga gate connected to a common wordline and each transistor having asource connected to an independently controllable bitline forindependently controlling said reflecting element to oscillate todifferent positions.
 43. The micromirror device of claim 42, wherein:each bitline connected to said source of said transistor is provided forreceiving a binary bit represented by zero and one for applying avoltage to said electrodes for independently controlling said reflectingelement to oscilate to different positions.
 44. The micromirror deviceof claim 42, wherein: each bitline connected to said source of saidtransistor is provided for receiving a binary bit represented by zeroand one for applying a voltage to said electrodes for applying one ofthree digital signals represented by (1,0), (0,1) and (0,0) forcontrolling said reflecting element to oscillate to three differentpositions.
 45. The micromirror device of claim 42, wherein: each bitlineconnected to said source of said transistor is provided for receiving abinary bit represented by zero and one for applying a voltage to saidelectrodes for applying one of three digital signals represented by(1,0), (0,1) and (0,0) for controlling said reflecting element tooscillate to angular positions oriented substantially at a positiveangle, a negative angle and 0° relative to a perpendicular axis to saidreflecting element.
 46. The micromirror device of claim 23, furthercomprising: said control circuit operated at a voltage substantiallyabout five volts for controlling said reflecting element to oscillate todifferent positions.
 47. The micromirror device of claim 23, wherein:said control circuit further receiving said control words having amaximum number of bits of at least ten bits for operating at a voltagesubstantially about twenty volts for controlling said reflecting elementto oscillate to different positions.
 48. The micromirror device of claim23, wherein: said micromirror device further constituting a CMOSmicromirror device.
 49. The micromirror device of claim 23, wherein:said micromirror device further constituting a DMOS micromirror device.50. The micromirror device of claim 23, wherein: said micromirror devicefurther constituting a PMOS micromirror device.
 51. The micromirrordevice of claim 23, wherein: said micromirror device furtherconstituting a NMOS micromirror device.
 52. The micromirror device ofclaim 23, wherein: said reflecting element further comprising a multiplelayer reflecting surface for improving reflectance from said reflectingelement.
 53. A method for controlling a micromirror device comprising:disposing a reflecting element supported on a hinge to oscillate betweentwo states and enabling said reflecting elements to project a partiallight for contributing to a display light intensity during oscillatingbetween either of said two states; receiving a series of control wordsof different number of bits as a time modulation signal to control saidreflecting element for controlling a gray scale of display; receiving anoscillation signal for superimposing on said time modulation signal foroscillating said reflecting element for further controlling said grayscale of display; and controlling said reflecting element by saidoscillating signal to oscillate to a fully on, a fully off and anpartially ON angular positions and further controlling said reflectingelement by said oscillating signal to change an oscillation direction inan intermediate angular position between said fully on and fully offangular positions.
 54. The method of claim 49, further comprising:applying a CMOS integrate circuit manufacturing process formanufacturing said micromirror device.